Pour the oil into a large pot, Dutch oven, or fryer. It should be at least 2 inches deep. Heat the oil to 375°F. If you don't own a candy or oil thermometer, simply sprinkle a pinch of flour into the oil. If it sizzles, it's ready.: When the oil heats, you want a steady environment that lets pieces float and fry evenly. Look for a glossy surface and a slow shimmer, not smoke. The ideal sound is a clear, active sizzle when you test with a pinch of flour; it should snap but not spit wildly. If you see heavy black smoke, the oil is too hot and will burn coatings, so lower the heat and let it cool slightly before testing again. Overcrowding the pot is a common mistake here because it drops the temperature and yields greasy results.
Meanwhile, put the flour in a shallow dish. Dredge the clams in flour and set aside. Repeat with the oysters, keeping the clams and oysters separate.: At this temperature, the flour coating crisps quickly, sealing in juices without overcooking the shellfish. If you have a thermometer, aim for a stable 375°F and watch for slight temperature dips between batches. Without a thermometer, sprinkle a pinch of flour into the oil; it should sizzle energetically and brown in a few seconds. A too cool oil will soak into the coating and feel heavy, while too hot oil will scorch the crust, so pacing and thermometer checks prevent disasters.
When the oil is hot, using a slotted spoon or spider, fry one test clam to ensure your oil is at the correct temperature. If your test is successful and the clam is pale golden, using a slotted spoon or spider, lower half of the clams into the oil and fry for 45 seconds, then transfer to a plate or baking sheet lined with paper towels to drain. Sprinkle liberally with salt. Repeat the process with the remaining clams, letting the oil return to temperature before frying the next batch.: Dry flour helps form the crust and gives each piece a consistent finish. As you dredge, pat excess flour off so you have a light coating rather than a thick batter. Keeping clams and oysters separate avoids cross contamination of cooking times and maintains clarity of texture. A mistake to avoid is letting the dredged pieces sit too long and absorb ambient moisture, which can make the crust fall off in the oil.
Next, fry half of the oysters. Using a slotted spoon or spider, lower half of the oysters into the oil and fry for 1 minute, then transfer to a plate or baking sheet lined with paper towels to drain. Sprinkle liberally with salt. Repeat the process with the remaining oysters, letting the oil return to temperature before frying the next batch.: A test piece confirms readiness and saves a whole batch from being ruined. The test clam should come up pale golden and crisp quickly. Listen for a lively sizzle that calms as the clam is removed; that indicates proper heat. If the test fritter sinks and does not brown, the oil needs to be hotter. One trap here is assuming the thermometer is correct without a test if your burner is finicky; the test keeps you honest.
Garnish the clams and oysters with fried sage leaves and serve with hot sauce, if desired.: The brief fry time preserves a juicy interior while giving a thin, crisp coating. You will hear a sustained sizzle and see tiny bubbles racing around the edges. Transfer to paper towels to wick away excess oil and sprinkle sea salt immediately so it sticks. Avoid crowding the basket because it will lower oil temperature and make results uneven.
Sprinkle liberally with salt: Salting right after frying is critical because the warmth helps the salt adhere and season through the crust. The grains create a bright counterpoint to the fried richness. A common misstep is waiting too long to salt, which leaves the exterior bland; salt while still warm for best flavor penetration.
Repeat the process with the remaining clams letting the oil return to temperature before frying the next batch: Patience between batches ensures each group hits the same thermal window for crispness. Use the test method again if the oil temperature wavers, and remove any small debris in the oil that could darken the next batch. Rushing by adding too many at once invites greasy, undercooked results, so keep the rhythm steady.
Next fry half of the oysters Using a slotted spoon or spider lower half of the oysters into the oil and fry for 1 minute then transfer to a plate or baking sheet lined with paper towels to drain: Oysters take marginally longer than littlenecks because their shape and moisture content need that extra moment to set the crust. Listen for a bright sizzle that keeps going for the full minute, and look for a uniform pale golden hue. Remove and let them drain briefly; should you see a dull, soggy surface, the oil was probably too cool, so adjust heat before the next batch.
Sprinkle liberally with salt: As with the clams, seasoning immediately after frying brings out the shellfish's natural flavors. The salt anchors the bite and balances the fried coating. One trap is using too fine a grind that dissolves away; medium flake sea salt gives a satisfying crunch and consistent seasoning.
Repeat the process with the remaining oysters letting the oil return to temperature before frying the next batch: By the final batches you will have a rhythm that helps you anticipate temperature dips and timing. Keep a small plate for finished pieces to avoid stacking while hot, which can steam and soften the crust. The most frequent mistake at this stage is impatience, leading to uneven doneness across pieces.
Garnish the clams and oysters with fried sage leaves and serve with hot sauce if desired: Quick frying the Fresh sage leaves imparts an aromatic, slightly bitter contrast that brightens the plate. They crisp in seconds and smell herbaceous and warm, like a fleeting autumn smell. Offer Tobasco on the side for anyone wanting vinegary heat. Avoid attempting to fry too many leaves at once because they can clump and become soggy rather than crisp.